Product : Fedora Core 4Name : flexVersion : 2.5.4a Release : 35.fc4 Summary : A tool for creating scanners (text pattern recognizers).Description :The flex program generates scanners. Scanners are programs which canrecognize lexical patterns in text. Flex takes pairs of regularexpressions and C code as input and generates a C source file asoutput. The output file is compiled and linked with a library toproduce an executable. The executable searches through its input foroccurrences of the regular expressions. When a match is found, itexecutes the corresponding C code. Flex was designed to work withboth Yacc and Bison, and is used by many programs as part of theirbuild process.

You should install flex if you are going to use your system forapplication development.